『Abstract
　The freshwater marshes in northern China are heavily impacted by anthropogenic disturbances such as cultivation and fertilization and increased levels of nutrients (especially N and P) through atmospheric deposition and agricultural surface runoff. These disturbances have affected the emission of N2O from these systems. This laboratory study was concluded to determine the effects of increased inputs of inorganic N and P on N2O emission from marsh soil in response to different soil moisture conditions. The results showed that the emission of N2O increased with the enhancement of N inputs when the soil was submerged, but that the highest N treatment suppressed the emission of N2O when the soil was at 60％ water holding capacity (WHC), which may have occurred due to an inadequate amount of available C. Furthermore, the results of this study indicated that a small amount of N fertilizer induced much more N2O evolution from freshwater wetland soil, while P fertilizer inputs appeared to stimulate the emission of N2O only during the first few days of the experiment. Additionally, soil that was treated with P appeared to absorb N2O when it was at 60％ WHC after around 6 weeks of the incubation, which indicates that the input of P fertilizer might serve as a shift of source or N2O sink in wetland soils under non-flooded conditions. When compared to soil at 60％ WHC, submerged soil had significantly higher N2O emissions, except when subjected to the medial N treatment. These findings indicate that the soil moisture condition had a significant effect on N2O emissions when the same amount of N or P was applied.Therefore, the effects of N and P fertilization in the northern temperate wetlands cannot be neglected from regional or national emissions of N2O.

Keywords: N fertilizer; P fertilizer; N2O emission; Soil moisture condition; Wetland』

Introduction
Materials and methods
　Soil sampling
　Fertilizers and soil moisture
　Experimental procedure
　Statistical analysis
Results
　Dynamics of N2O emission rate in response to N fertilizer
　Dynamics of N2O emission rate in response to P fertilizer　
　Cumulative emissions of N2O with time as affected by N fertilizer
　Cumulative emissions of N2O with time as affected by P fertilizer
Discussion
　Soil moisture condition
　N application effect
　P application effect
　The potential effects of increased N and P fertilization on N2O emission from freshwater marsh soil
Conclusions
Acknowledgments
References